HP 54601a question/help repairing

[Hrenowsky]

Hi!

I recently got an old hp 54601a 4 channel oscilloscope which my company was going to throw away. As i hate to throwing away stuff that works, i gladly gave it a new home.

But it has two problems.

1st is the common squished vertical display - i have found multiple threads already for fixing it, so that won't be a problem.

2nd is more of a question on the oscilloscope's operation. And basically the reason why it was scrapped.

It has a problem with displaying square waves. When a square wave is applied, the scope only shows the horizontal lines, verticals are only a few dots (can still kinda be seen just very dimm).
My coworker told me, that it's because the scope is so old, but I'm kinda skeptical about that

I've searched the web, but haven't found anything on the issue or did i find any pics or videos of the scope in use (only foud the tetris easter egg [emoji16])

Soo... if anyone has any ideas or can clarify why vertical lines don't work, I'd greatly appreciate the info!




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[JFJ]

The maximum sample rate of the HP 54601A is 20 MS/s. Consequently, it does not capture many samples during the fast rising/falling edges of a square wave. Hence, the few dots. Many oscilloscopes in the HP 546xxx range have the facility to join the dots - using the 'Vectors On' option, in the 'Display' menu. The HP 54601B oscilloscope definitely has that option, but the HP 54601A may not.

[Bushougoma]

As probably mentioned in the other thread a partially collapsed vertical deflection is a common failure with CRTs in general when one of the caps around the vertical deflection IC goes bad.

Sadly the only scopes worth having in the 54600 series are the 54645A and 54645D 200 MS/s scopes they have the first generation Megazoom ASIC and 1 MB of memory per scope channel.

I wouldn't use that scope for anything but repetitive measurements but hey you can't beat the price .